America's Got Talent sensation Grace VanderWaal knocked it out of the park again on the season finale Tuesday night.

The 12-year-old singer and ukulele player once again earned a standing ovation from all four judges after performing her original song "Clay."

Judge Howie Mandel, who sent VanderWaal into the stratosphere when he picked her for his Golden Buzzer, gave her high praise: "Amazing Grace, how sweet the sound," he said. "It's not only a song -- it speaks to you. You are amazing. This is my favorite moment of the night."

Mel B told VanderWaal she was in her "ultimate element tonight," declaring: "You're meant to be here."

Heidi Klumcompared her to "the most original diamond, or the rarest diamond, of them all."

Simon Cowell -- who predicted VanderWaal as the new Taylor Swift after her audition -- envisions a bright future for the preteen.

"People are going to look back at you [and say] you did it in a real way. No gimmicks. It was just you," Cowell said. "You deserve your place tonight. I don't know what's going to happen, but you're going to be there at the end. I can feel it."

VanderWaal has been fiercely original for the entire season, unveiling the self-penned songs "I Don't Know My Name," "I'll Hold Your Hand" and "Light the Sky," and inspiring other ukulele-toting musicians on YouTube to cover her music.